Edwaed webton



I (NOM0de1.)-

E. WESTON.

MANUFACTURE OF CARBON CONDUCTORS FOR INCANDESCENT ELECTRIC LIGHTS.

No, 340,397. C Patented Apr. 20, 1886.

UNITED STATES PATENT 'QFFICE;

EDWARD WESTON, OF NEWVARK, NE? JERSEY, ASSIGNOR TO THE UNITED STATESELECTRIC LIGHTING COMPANY, OF NEW YORK N. Y.

MANUFACTURE OF CARBON CONDUCTORS FOR INCANDESCENT ELECTRIC LlGHTS.

SPECIFICATION forming part of Letters Patent No, 340,397, dated April20, 1886.

Application filed September 9, 1885. Serial No. 176,552. (No model.) I

To all whom it may concern:

Be it known that I, EDWARD WEsToN, a subject of the Queen of GreatBritain. and a resident of Newark, in the county of Essex and State ofNew Jersey, have invented certain new and useful Improvements in theManufacture-of Carbon Conductors for Incandescent Electric Lamps, ofwhich the following is a specification, reference being had to thedrawings accompanying and forming a part of the same.

I will first describe the general nature of the method or processinvolving my improvements, and then indicate more particularly thespecial features of novelty which I here claim.

I prepare from a suitable carbonizable material straight strips orfilaments of carbon without enlargements of any kind. I prefer to usethe material now known as tamidine, though others maybe employed forthis purpose.

It is desirable, and, in fact, necessary to the economical andpracticable manufacture of the lamps, that the ends of the carbon towhich the supporting-wires are joined should be somewhat enlarged, and Iprefer for many rea sons to form these enlargements by electricallyheating the conductors near their ends only in a hydrocarbon vapor orliquid; but I have found that to simply place the carbons as they aretaken from the carbonizing muffle or retort in the stub-formingapparatus yields very poor results. Oarbons made in this way seem to beimperfect from the fact that the certain gases which seem to be retainedby the carbon are'not driven off. To remedy this I mount the carbons,just as they are when taken from the carbonizingmuffle, in a temporaryreceiverand by an elec tric current I raise them to a very highincandescence. To do this without injury to the carbon the air must bevery perfectly exhausted from the receiver, or, what is much easier andequally effective, a small quantity of a hydrocarbon or similar vaporshould be introduced after roughly exhausting the receiver. The degreeof incandescence to which the carbons are thus raised should be somewhathigher than that at which they are expected to run under normalconditions of use, and it is only necessary to maintain them so for afew seconds. In this treatment all but the extreme ends of the carbonsare rendered incandescent, and the retained gases driven oft. Thecarbons are then removed and placed in any convenient form of apparatusby which a small portion of each end is rendered incandescent in a vaporor liquid that forms on them a deposit of carbon, and in this way theenlarged ends or stubs are formed. The eX- treme ends, which have beenin the clamps in both of the devices above described, and consequentlynot raised to a very high temperature nor sensibly coated by the carbonde- 6 5 posit, are broken off before the carbons are mounted orsubjected to any other treatment.

In the drawings I have illustrated the various steps or stages of thisprocess.

Figure 1 represents the carbon before treatment. Fig. 2 is a sideelevation of an ordinary form of apparatus for raising the carbon toincandescence. Fig. 3 is an apparatus for forming the stubs, and Fig. 4is the carbon witht-he enlarged ends or stubs.

The apparatus in Fig. 2 is a simple receiver connected by a tube, A,with an air-pump. Under the glass B are clamps G, in which a carbon isplaced, and after the air has been exhausted and a small quantity ofgasoline or 80 similar vapor admitted it is raised to a high point ofincandesceuce. The carbon is then placed in a receptacle, D, containingpetroleum or gasoline or the like, and held by clamps E, to which theelectrical connections are made, '85 as indicated by the dotted lines.When the enlargements F have been formed, the endsf are broken off andthe carbon mounted in a lamp or subjected to whatever treatment may beconsidered desirable or necessary. By this 0 process the entire carbonundergoes an operation by which the retained gases are expelled beiorethe deposited ends are formed.

The carbons are standardized-after the ends are formed by mounting themin a receiver 5 similar to that shown in Fig. 2, containing a rarefiedhydrocarbon vapor, and heating them by a currentuntil by the depositionof carbon their resistance is brought to a certain point. This process,which is commonly known as too treating, is effected to small degree bythe l may be contained in thecarbon, but to compreliminary processherein described for expelling the occluded gases. The two steps plete aprocess of carbonization which no other process of which I an: aware iscapable of fully are, however, distinct, as in the real processeffecting.

of treating the temperature, at leastat the start, is very much lower,and in the firstnamed step the vapor is only employed in or der to avoidthe use of a high-vacuum apparatus.

I have found that carbons of rior qualities are produced in the wayabove f described.

It has been usual heretofore to form the ends or stubs by the depositionof carbon to lower the resistance of the carbons by heating them in ahydrocarbon vapor, and to expel the gases from the carbon by raising itto a high degree of incandescence during the process of exhausting thelamps or while the lamps are on the pumps; but this process in volvesthe novel features of raising for ashort time the carbons to highincandescence before either the ends are enlarged or the carbons Istandardized. treatment is not only to expel such The probable effect ofthis, gases as I What I claim is 1. The method or process ofmanufacturing carbon conductors, which consists in raising the carbonsto high incaudescence by an electric current and then heating thecarbons at greatly supeor near the ends only in a hydrocarbon or similarvapor or oil, to form enlarged stubs thereon, as set forth.

2. The method or process of manufacturing carbonconductors, whichconsists in raising the carbons to high incandescence by an electriccurrent, then heating the carbons at or near the ends only in ahydrocarbon vapor or oil, to form enlarged stubs thereon, and thenheating the entire carbons in a similar vapor until their electricalresistance is brought to the desired point, as set forth.

EDWARD WESTON.

\Vituesses:

FRANK N. CRANE, FRANK H. KING.

